Apparatus for adapting the diameter of a disk-like recording medium

ABSTRACT

Described is an apparatus for adapting the diameter of the disk-like recording medium. The apparatus includes a supporting member in the form of a ring having an opening for exposing the signal record area of the disk-like recording medium, such as an optical disk, to the outside, and having a diameter larger than the diameter of the disk-like recording medium. The recording medium is integrally retained by a holding system provided to the supporting member for holding the outer perimeter of the recording medium.

This is a division of application Ser. No. 162,203, filed 2-29-88 nowU.S. Pat. No. 4,837,784.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an apparatus for adapting the diameter of adisk-like recording medium, such as an optical disk, opto-magnetic diskor a magnetic disk, wherein the recording medium is held on the innerperiphery of a holder to permit the diameter of the disk-like recordingmedium to functionally assume the outside diameter of the holder.

2. Prior Art

An optical disk player has been employed in which prescribed informationsignals recorded on an optical recording medium are read and reproducedby contactless scanning by an optical pickup device adapted for signalreading.

In the above type disk player, the optical disk has only its centralnon-signal record area clamped by a disk table of a disk driving unitand clamping members securely pressured to the disk supporting side ofthe disk table. The optical disk is made as one with the disk table andcaused to be revolved in unison therewith with the signal record areathereof facing to the optical pickup device.

In the above described disk player having the disk drive unit and thecontactless optical pickup device, it is necessary that the disk driveunit mounting the optical disk and the optical pickup device beaccurately positioned relative to each other for achieving accuratereading and reproduction of the information signals from the opticaldisk. Thus, in this type of the disk player, the disk drive unit issupported with accurate positioning by a chassis base plate provided inthe main body of the player, while the optical pickup unit is slidablysupported on a guide shaft mounted with accurate positioning to thechassis base plate.

Thus the disk loading device in which the optical disk employed in theabove disk player is automatically mounted to the disk drive unit is soarranged as to transport only the optical disk for attachment thereof tothe disk drive unit.

There is so far known a disk player having a disk loading device such asshown in the Japanese Laid-open Utility Model Application No.145367/1986 or in the Japanese Laid-open Patent Publication No.231966/1985.

In the disk player as shown in the Japanese Laid-open Utility ModelPublication No. 145367/1986, a disk transfer table 3 on which rests anoptical disk 2 is mounted so as to be movable into and out of a mainbody of the player 1, see FIG. 1. The disk transfer table 3 istransferred into the interior of the main body of the player 1 in thedirection shown by the arrow mark a in FIG. 2 by a driving gearing 5actuated by a driving motor 4 until the optical disk 2 held in anannular recess 6 formed on the table 3 is at a position confronting adisk table 9 of a disk drive unit 8 supported on a chassis base plate 7within the main body of the player 1, see FIG. 3. A disk supportingmember 3a projecting vertically movably from the bottom surface of theannular recess 6 for supporting the optical disk 2 may be actuated sothat the optical disk may be placed on and attached to the disk table 9with a central opening 2a of the optical disk 2 in alignment with thecenter of the disk table 9. After the optical disk 2 is attached in thismanner to the disk table 9, a chucking arm 11 is turned towards the disktable 9 in the direction shown by the arrow mark X in FIG. 3 until adisk clamper 12 attached to the end of the chucking arm 11 is pressuredonto the optical disk 2 so that the optical disk may be revolved inunison with the disk table 9.

The optical disk 2 thus clamped to the disk table 9 is confronted by anoptical pick-up unit 14 slidably supported by guide shafts 13, 13mounted to the classis base plate 7.

In a disk loading device of the type in which the optical disk 2supported on the disk transfer table 3 movable with respect to the mainbody of the player 1 is mounted on the disk table 9 within the main bodyof the player 1, it is necessary that the optical disk 2 be supported atthe controlled position on the disk transfer table 3, so as to providefor accurate and positive attachment of the optical disk to the disktable 9. To this end, the annular recess 6 formed on the disk transfertable 3 has the radius R₄ corresponding to the radius R₃ of the opticaldisk 2 supported therein and the outer peripheral surface 2a of theoptical disk 2 is supported by the upright peripheral surface 6a of theannular recess 6 to control the support position of the disk 2.

In a disk player shown in the Japanese Laid-open Patent Publication No.231966/1985, a disk inserting opening 16 is provided in the main body ofthe player 15, see FIG. 4. In the vicinity of the disk inserting opening16, there are provided a stationary guide plate 20 and a movable guideplate 19 facing to the stationary guide plate and mounted through themedium of the loading arms 18, 18, rotatably supported by frames 17, 17,see FIG. 5. The optical disk 2 is adapted to be introduced into the mainbody of the player 15 through a gap formed by these guide plates 19, 20.A pair of rolls, that is, a stationary roll 21 and a driving roll 22,each having a reduced diameter at the center and having the diametergradually increasing towards both ends, are provided at a position toreceive the disk 2 inserted through the gap defined between these guideplates 19, 20. The optical disk 2 is clamped between these rolls 21, 22.The driving roll 22 is transferred onto the disk table 9 of the rotarydriving unit 8 mounted in the inside of the main body of the player 15by a driving electric motor 24 through a drive gearing 23 as shown inFIG. 6 for mounting the disk.

In the above disk player, when the optical disk 2 has been transferredonto the disk table 9, the loading arms 18, 18 are turned to lower thedriving roll 22 and the movable guide plate 19 for attaching the disk tothe disk table 9 with the central opening 2a of the disk 2 in alignmentwith the center of the disk table 9. Following the lowering of the roll22 and the guide plate 19, the chucking arm 11 is turned until the diskclamper 12 provided to the arm end is pressured onto the optical disk 2so that the disk is clamped for rotation in unison with the disk table9.

There is also known a disk player in which the optical disk is notclamped automatically to the disk table but in which a cover fitted witha disk clamper in opposition to the disk table of the disk drive devicemounted in a substantially vertical position within the main body of theplayer is mounted for rotation relative to a player cabinetaccommodating the main body of the player, so that the disk 2 is clampedfor rotation in the upstanding position. The cover is provided with adisk position regulating member adapted for regulating the radial strokeof the disk to provide for an optimum disk clamping by the disk clamperand the disk table. This cover is rotated with the disk placed thereonwith the stroke of the disk movement being controlled by the diskposition regulating member so that the optical disk is clamped to thedisk table.

In the above disk player, the disk position regulating member providedto the cover is provided at a position corresponding to the outerperiphery of the disk for coinciding the central opening of the opticaldisk with the center of the disk table for centering the disk relativeto the disk table to regulate the position of the optical disk.

In the above disk players, an optical disk having a predeterminedunified disk diameter is necessarily employed. Thus the followingproblems are presented when an optical disk having different sizes asdescribed above are to be reproduced by the above disk players. In thedisk player disclosed in the aforementioned Japanese Laid-open UtilityModel Publication No. 145367/1986, disk movement is regulated with theouter peripheral surface 2a of the optical disk 2 abutting on theupright peripheral wall 6a of the annular recess 6 formed on the disktransfer table 3 for matching the disk position relative to the disktable 9. Thus an optical disk other than the optical disk mating withthe annular recess 6 cannot be transported at a predetermined supportposition. Thus disks of different sizes cannot be attached to the disktable 9 with correct centering, so that the disk cannot be clamped bythe disk clamper 12 for rotation.

In the disk player shown in the aforementioned Japanese Laid-open PatentPublication No. 231966/1985, the optical disk 2 inserted through thedisk inserting opening 16 is clamped by the stationary roll 21 and thedriving roll 22 so as to be transferred and attached to the disk table 9in the main body of the player 15. Thus an optical disk of a size otherthan a prescribed size cannot be centered with respect to the disk table9 because the disk 2 then has a variable transfer stroke such that thedisk cannot be clamped by the disk clamper 12 for rotation.

In the above described disk player in which the cover is rotatablymounted to the main body of the player and the disk regulated in itsposition is attached to the disk table, position matching between thedisk and the disk player is achieved by having the outer peripheral edgeof the optical disk supported as described above. Thus, when an opticaldisk of a different size is placed on the cover and the latter is turnedin a direction to clamp the optical disk, the center of the optical diskcannot be coincided with that of the optical disk or that of the diskclamper and thus correct positioning cannot be achieved. Thus it is notpossible to clamp the disk by the disk table and the disk clamper andthus it is not possible to rotate the disk.

There has been proposed an optical disk having a variable size independence upon the amount of recorded information. Since the opticaldisk is capable of recording an extremely large number of informationsignals, when recording a small amount of the information signals, suchas only one or two numbers, the majority of the signal record arearemains void or free of recorded signals. Thus an optical disk of areduced size has been proposed in order to make an efficient use of thedisk material and the signal record area so as to provide for simplifiedhandling and to adapt the disk to the amount of the recordedinformation.

However, such small size optical disk has a drawback that it cannot beloaded in the above described conventional disk layers for recording orreproduction.

OBJECT AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide anapparatus for adapting the disk diameter wherein a disk with a diameterless than that of a disk having the unified prescribed outside diametercan be made to be handled in the same way as the disk of the unifieddiameter to make possible loading thereof into aforementionedconventional extensively employed disk players.

The present invention provides an arrangement wherein the outerperiphery of the disk-like recording medium is held by the innerperiphery of a toroidal holder, to the inner periphery of which thedisk-like recording medium is fitted, in order to provide for unifyingthe small size disk with respect to the size or diameter to the disk ofthe unified size or diameter.

According to the present invention, the recording medium may besubstantially assimilated in diameter to the outside diameter of theholder, by having the disk-like recording medium, such as the opticaldisk held by holding means provided to the inner periphery of theholder, so as to render the holder as one with the disk-like recordingmedium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a known dish player having a disktransfer table; FIG. 2 is a plan view showing the inside structure ofthe disk player of FIG. 1; and FIG. 3 is a side view illustrating astate of a clamping operation of an optical disk.

FIG. 4 is a perspective view of another known disk player wherein aloading operation of an optical disk is accomplished by a pair of rolls;FIG. 5 is a perspective view showing the inside structure of the diskplayer of FIG. 4; and FIG. 6 is a plan view showing a state of a loadingoperation of the optical disk.

FIG. 7 is a perspective view showing a first embodiment of an apparatusfor adapting the diameter of a disk-like recording medium of the presentinvention; FIG. 8 is a plan view illustrating a state with a small sizedisk being held; and FIG. 9 is an enlarged sectional view takensubstantially along line A-A of FIG. 2.

FIG. 10 is a perspective view of a second embodiment of an apparatus foradapting the diameter of a disk-like recording medium of the presentinvention; FIG. 11 is a plan view showing a state with a small size diskbeing held; FIG. 12 is an enlarged sectional view taken along line B--Bof FIG. 11, with portions broken away; FIG. 13 is a plan view showing astate of a small size disk being held; FIG. 14 is an enlarged sectionalview taken along line C--C of FIG. 13, with portions broken away; andFIG. 15 is an enlarged sectional view taken along line D--D of FIG. 13.

FIG. 16 is a plan view of a third embodiment of an apparatus foradapting the diameter of a disk-like recording medium of the presentinvention; FIG. 17 is an enlarged sectional view taken along line E--Eof FIG. 16 with portions broken away; FIG. 18 is an enlarged sectionalview taken along line F--F of FIG. 16 with portions broken away; FIG. 19is an enlarged sectional view taken along line G--G of FIG. 16; FIG. 20is an enlarged sectional view taken along line HH of FIG. 16; FIG. 21 isa plan view showing a state of a small size disk being held; and FIG. 22is an enlarged sectional view taken along line I--I of FIG. 21 withportions broken away.

FIG. 23 is an exploded perspective view of a fourth embodiment of anapparatus for adapting the diameter of a disk-like recording medium ofthe present invention; FIG. 24 is a plan view of a disk supportingmember which constitutes said apparatus; FIG. 25 is a plan view of adisk clamping member which constitutes said apparatus; FIG. 26 is a planview showing a state of a small size disk being clamped; FIG. 27 is anenlarged sectional view taken along line J--J of FIG. 26; and FIG. 28 isan enlarged sectional view taken along line K--K of FIG. 26.

FIG. 29 is a perspective view of a fifth embodiment of an apparatus foradapting the diameter of a disk-like recording medium of the presentinvention; FIG. 30 is a plan view of a disk supporting member whichconstitutes said apparatus; FIG. 31 is a plan view of a disk clampingmember which constitutes said apparatus; FIGS. 32 and 33 are a plan viewand a bottom view, respectively, illustrating a state of a small sizedisk being clamped; and FIGS. 34 and 35 are a plan view and a bottomview, respectively, illustrating a clamping state of the small sizedisk.

FIG. 36 is a perspective view showing an entirety of a sixth embodimentof an apparatus for adapting the diameter of a disk-like recordingmedium of the present invention; FIG. 37 is a plan view of a disksupporting member which constitutes said apparatus; FIG. 38 is a planview of a disk holding member which constitutes said apparatus; FIG. 39is a plan view illustrating a state of a small size disk being held bythe apparatus for adapting the diameter of a disk-like recording mediumaccording to the present invention; FIG. 40 is a plan view of a state ofholding the small size disk; FIG. 41 is a sectional view taken alongline L--L of FIG. 40; FIG. 42 is a sectional view taken along line M--Mof FIG. 40; and FIG. 43 is a sectional view taken along line N--N ofFIG. 40.

DESCRIPTION OF PREFERRED EMBODIMENTS

By referring to the accompanying drawings, certain preferred embodimentsof the present invention will be explained in detail.

The first embodiment of the apparatus for adapting the disk diameteraccording to the present invention will now be explained.

The apparatus shown herein has a toroidal holder 125 having an outsidediameter R₁ equal to the radius R₃ of the aforementioned optical disk 2which is a conventional so called compact disk having a unified disksize of 12 cm as shown in FIG. 7.

The holder 125 is formed of synthetic material having prescribedrigidity, such as the ABS resin, and has a thickness approximately equalto that of the optical disk 2. On the side of the inner periphery of theholder 125, there is formed a disk fitting opening 127 in which there isfitted a small size disk 126 having a disk diameter R₂, for example 8cm, which is less than that of the aforementioned unified optical disk2. On the periphery of the fitting opening 127, there is mounted atoroidal disk holding member 128 made of rubber or a resilient syntheticmaterial as the holding means for holding the outer peripheral portion126a of the small size disk 126. As shown in FIG. 9, the disk holdingmember 128 is comprised of a disk holding portion 130 having its innerperipheral surface formed with a disk engaging groove 129 adapted forengaging with the outer peripheral portion 126a of the small size disk126, and a pair of clamping pieces 131, 132 for the holder 125 extendingoutwardly from the disk holding portion 130. On the inner side of theclamping piece 131, there are formed a number of engaging projections134 adapted for engaging in a corresponding number of mating engagingopenings 133 formed in the holder 125 along the disk fitting opening127. The disk holding member 128 arranged ad constructed as describedabove is fitted to the inner periphery of the holder 125, as shown inFIGS. 7 and 8, with the clamping pieces 131, 132 clamping the peripheryof the holder 125 in the vicinity of the disk fitting openings 127 andwith the engaging projections 134 engaging with the mating engagingopenings 133.

It is noted that the portion of the holder 125 clamped by the clampingpieces 131, 132 is formed with steps 135, 136 and thus reduced inthickness such that the clamping pieces 131, 132 lie substantially flushwith both sides of the holder 125.

It is noted that, when only one side of the small size disk 126 isdesigned as the signal record surface, the disk 126 can be attached tothe optical pickup device in the disk player only in a predeterminedattachment orientation. For indicating the attachment orientation of thesmall-size disk 126, the one surface of the holder 125 is designed as amirror surface 125a, that is, the surface having the same opticalproperties as those of the optical recording medium of the small sizedisk 126, which mirror surface has the appearance similar to that of thesignal record surface 126b of the small size disk 126. The other surfacethereof is designed as a printed surface bearing printed handlinginstructions similarly to the other face 126c of the small size disk126.

It is noted that, for indicating the attachment orientation of the smallsize disk 126, any other indicating means such as labels or stamping maybe employed.

In the above described disk diameter change device, the small size disk126 is fitted to the disk holding member 128 with the signal recordsurface 126b laying on the same side as the mirror surface 125a of theholder 125. When the small size disk 126 is to be introduced into thedisk holding member 128, the disk engaging groove 129 is deformedresiliently so that the outer peripheral portion 126a of the disk 126 isintroduced and fitted into the disk fitting groove 129 to maintain thesmall size disk 126 as indicated in FIG. 8.

With the small size disk 126 supported in this manner, the disk 126 ismade as one with the holder 125 and thus the resulting assembly isequivalent to the aforementioned optical disk having the unified diskdiameter so that the assembly can be handled in the same manner as theaforementioned optical disk

A second embodiment of the disk radius change device according to thepresent invention will now be explained.

The apparatus for adapting the disk diameter shown herein also has atoroidal holder 141 having the outside diameter R₁ equal to the diskdiameter R₃ of the optical disk 2 which is the conventional and widelyemployed so-called compact disk with the unified disk size or diameterof 12 cm, as shown in FIG. 10, similarly to the preceding embodiment.

The holder 141 is formed of synthetic material having prescribedrigidity, such as ABS resin, and has approximately the same thickness asthe aforementioned optical disk. The inner peripheral side of the holder141 is formed with a disk fitting opening 142 into which a small sizedisk 126 is fitted having a radius R₂ of, for example, 8 cm, which isless than that of the aforementioned unified optical disk, as shown inFIGS. 10 and 11. On the periphery of the opening 142, the holder 141 isformed with three equiangular disk holding sections 143 that may beresiliently deflected radially of the holder 141. Each of these diskholding sections 143 is formed integrally in the holder 141 by forming apair of slits 144, 145 radially extending some distance from the diskfitting opening 142 and a peripheral slit 146 extending from near theend portions of and between these slits 144, 145. The peripheral slit146 is comprised of a central slit portion 146a protruding towards theouter periphery of the holder 141 and two side slit portions 146b, 146cextending from both ends of the central slit 146a towards the ends ofthe radial slits 144, 145 and protruding in a reverse direction, thatis, towards the disk fitting opening 142. The disk holding section 143formed in this manner by boring the peripheral slit 146 has its centralwidened portion 143a supported by a pair of continuous narrow armportions 143b, 143c, and is so designed that the widened portion 143amay be supported resiliently and radially of the holder 141 within theextent of the gap of the peripheral slit 146 with the continuous armportions 143b, 143c being used as the resilient deflective portions.

The side edge of the widened portion 143a of the disk holding portion143 towards the disk fitting opening 142 is formed with a disk retainingportion 148 protruding towards the disk fitting opening 142 and havingan engaging groove 147 adapted to be engaged with the outer peripheralportion 126a of the small size disk 126, as shown in FIG. 12. Therefore,the distance from the center of the holder 141 to the disk retainingportion 148 is selected to be smaller than the radius of the small sizedisk 126 approximately by the gap of the peripheral slit 146. The oneside of each widened portion 143a is formed with a finger restprojections 149 formed by recesses or grooves for facilitating theoperation of resiliently deflecting or enlarging the diameter at thedisk holding portion 143 during the operation of fitting the small sizedisk 126.

It is noted that, on the confronting sides of the radially extendingslits 144, 145 and the peripheral slit 146, steps or projections 150a,150b, 151a, 151b are formed, as shown in FIGS. 14 and 15. When the smallsize disk 126 is attached to the holder 141 to cause resilientdeflection of the disk holding sections 143, these steps 150a, 150b,151a, 151b are engaged with one another to close the slits 144, 145 and146. Similarly to the preceding first embodiment, the one side of theholder 141 of the present embodiment is formed as a mirror surface 141ahaving an appearance similar to that of the signal recording surface126b of the disk 126, while its other side is formed as a printedsurface bearing printed handling instructions similarly to the otherside 126c of the disk 126, for clarifying the attachment orientation ofthe small-size disk 126.

When attaching the small size disk 126 to the apparatus as describedabove, the outer peripheral portion 126a of the small size disk 126 isengaged with the engaging groove 147 of one of the disk holding portions143, with the mirror surface 125a of the holder 141 lying on the sameside as the signal recording surface 126b of the small size disk 126,and the disk holding section 143 is resiliently deflected to increaseits diameter for fitting the small-size disk 126 in the disk fittingopening 142. Following this operation, the remaining disk holdingsections 143 are also resiliently deflected by applying the fingerpressure so as to be increased in diameter, the outer peripheral portion126a of the small-size disk 126 being engaged in the engaging grooves147 of these disk holding sections 143. In this manner, the small sizedisk 126 is made as one with the holder 141 and the resulting assemblyhas the same diameter as that of the aforementioned optical disk havingthe unified disk size so that it can be handled in the same manner asthe optical disk.

It is noted that the confronting sides of the radially extending slits144, 145 and the peripheral slit 146 formed in the holder 141, areformed with steps or projections 150a, 150b, 151a, 151b meshing with oneanother to close the radially extending slits 144, 145 and theperipheral slit 146 when the small size disk 126 is held therein asdescribed hereinabove. In this manner, when the small-size disk 126 isheld and attached to the disk player and irradiated with a laser beamfrom an optical pickup device, transmission leakage of the laser beam(or of the light beam from a detector in the case of a disk playerhaving a detecting unit adapted for detecting the start or end of diskloading by the light beam from the detector) may be prevented fromoccurring. Thus the disk utilizing a laser beam may be handled in thesame manner as the optical disk having the unified disk size.

It is noted that, for further assuring tight sealing of the small-sizedisk 126 during attachment thereof, bosses or projections, not shown,may be mounted to one of the disk fitting openings 142 for sealing.

A third embodiment of the disk size change device according to thepresent invention will be hereafter explained. It is noted that, in theabove described second embodiment, three equiangular resilientlydeflectible disk holding sections are provided at the inner periphery ofthe holder, these three disk holding sections holding the small sizedisk. However, only one resiliently deflectible disk holding section maysuffice, as shown in FIG. 16.

Similarly to the first and second embodiments, the apparatus foradapting the disk diameter shown in FIG. 16 has a toroidal holder 161having an outside diameter R₁ equal to the diameter R₃ of the opticaldisk 2 (diameter, 12 cm) which is the so-called compact disk having theunified size or diameter. The holder 161 is also formed of syntheticmaterial having rigidity similar to the holder of the precedingembodiments, such as ABS resin, and has a thickness approximately aboutequal to that of the optical disk.

The inner periphery of the holder 161 is formed with a disk fittingopening 162 in which a small size disk 126 having a disk diameter R₂,for example 8 cm, which is less than that of the unified optical disk 2,is fitted, as shown in FIG. 16. On the periphery of the fitting opening62, supporting tongues 163 adapted for supporting the outer peripheralportion 126a of the small size disk 126 are projectingly formed from theone main surface 161a lying on the same side as the signal recordsurface 126b of the small size disk 126 when the disk 126 is fitted intodisk fitting opening 162. These supporting tongues 163 are of asufficiently reduced thickness and of a width to support only thenon-signal record area of the outer peripheral portion 126a of the smallsize disk 126. On the perimeter of the fitting opening 162 and at twoplaces spaced apart a predetermined angular distance from each other,there are formed so as to protrude from the other main surface 161bfacing to the surface provided with the supporting tongues 163,thrusting and supporting tongues 164, 164 adapted for thrusting andsupporting the outer peripheral portion 126a of the small size disk 126in cooperation with the supporting tongues 163. These thrusting andsupporting tongues 164, 164 are projectingly formed towards the innerperiphery of the fitting opening 162 and of substantially the same widthas that of the supporting tongues 163, as shown on FIG. 18. The portionsof each of the supporting tongues 163 corresponding to the positions ofthe thrusting and supporting tongues 164, 164 are formed as recesses165, 165 in order to assure the withdrawal of the metal mold duringmolding of the thrusting and supporting tongues 164, 164.

On the perimeter of the fitting opening 162 of the holder 161, there areformed disk holding sections 166 integrally with the holder 161, thesedisk holding sections being in register with the thrusting andsupporting tongues 164, 164 and capable of being resiliently deflectedradially of the holder 161. The disk holding sections 166 are comprisedof a pair of cut-outs 167, 168 spaced apart from each other at aprescribed distance and extending from the disk fitting opening 162towards the outer periphery of the holder 161, and a peripheral slit 169extending between and from near the end parts of these slits 167, 168.The central slit portion 169a of the peripheral slit 169 is protrudedtowards the outer periphery of the holder 161, while the two side slitportions 169b, 169c extending from both ends of the central slit portion169a towards the end positions of the cut-outs 167, 168 are protruded inthe opposite direction, that is, towards the disk fitting opening 162.The disk holding section 166 thus formed by boring the peripheral slit169 is so designed that the central widened portion 166a is supported bya pair of narrow continuous arm portions 166b, 166c and the widenedportion 166a is resiliently deflectibly supported radially of the holder161 within the extent of the gap of the peripheral slit 169, with thesecontinuous arm portions 166b, 166c as the resiliently deformableportions.

The side edge of the widened portion 166a of the disk holding section166 lying towards the disk fitting opening 162 is provided with athrusting and supporting piece 170 projecting from the other mainsurface 161b of the holder 161 for thrusting and supporting theperipheral portion 126a of the small size disk 126, see FIG. 17. Thedistance from the center of the holder 161 to the thrusting andsupporting piece 170 is selected to be less than the radius of the smallsize disk 126 approximately by the gap of the peripheral slit 169. Onthe other main surface 161b, the widened portion 166a is formed with afinger rest projections 171, formed by recesses or slots, forfacilitating the operation of resiliently deflecting or enlarging thediameter of the disk holding section 166 during the fitting operation ofthe small size disk 126.

The portion of the holder 161 extending from the disk holding portion166 to the narrow continuous arm portions 166b, 166c is cut-out on theone main surface 161a thereof to provide for reduced thickness of thedisk holding section 166. In the portion of the peripheral slit 169corresponding to the cut-out portion of the holder 161, a step orprojection 172 is provided for closing the peripheral slit 169 when thesmall radius disk 126 is fitted for resiliently deforming the diskholding section 166, see FIG. 19.

The portions of the holder 161 formed with the cut-outs 167, 168 areformed with sealing tongues 173, 173 projecting from the one mainsurface 161a of the holder 161 and extending from the roots of thecontinuous arm portions 166b, 166c of the disk holding section 166 tothe cut-outs 167, 168, as shown in FIG. 20. These tongues 173, 173 areused for preventing the laser beam from an optical pickup deviceprovided to the main body of the player or the light beam from detectingmeans adapted for start or termination of the disk loading operationfrom being transmitted through the cut-outs 167, 168. It is noted that,for assuring resilient deformation of the continuous arm portions 166b,166c, of the disk holding section 166 despite the presence of thesesealing tongues 173, 173, a slot 174 is formed in a manner of dividingthe continuous arm portions 166b, 166c as shown in FIG. 20.

Similarly to the preceding first and second embodiments, the one side ofthe holder 161 of the present embodiment is formed as a mirror surfacehaving an appearance similar to that of the signal record surface 126bof the disk 126, while its other side is formed as a printed surfacebearing printed handling instructions similar to the other side 126c ofthe disk 126, for clarifying the attachment orientation of the smallsize disk 126.

When attaching the small size disk 126 to the apparatus for adapting thedisk diameter as described above, the outer peripheral portion 126a ofthe small size disk 126 is caused to rest on the supporting tongues,with the one main surface 161a of the holder 161 lying on the same sideas the signal record surface 126b of the small size disk 126, while theother main surface of the small size disk 126 is placed within the diskfitting opening 162 as it is thrusted and supported by the thrusting andsupporting tongues 164, 164. The small size disk 126 is then fitted inthe disk fitting opening 162 while the disk holding section 166 isresiliently deflected so as to be enlarged in diameter, after which thedisk may be clamped by the supporting tongues 163, thrusting andsupporting tongues 164, 164 and the thrusting and supporting pieces 170by the springback of the disk holding sections 166. As shown in FIG. 21and 22, the small size disk 126 is made as one with the holder 161 sothat an assembly having the same diameter as that of the aforementionedoptical disk with the unified disk diameter is provided, which assemblycan be handled in the same manner as the optical disk.

A fourth embodiment of the disk size change device according to thepresent invention will be hereafter explained.

Similarly to the above described preceding embodiments, the disk sizechange device shown herein is comprised of a small size disk 225 havinga diameter of, for example, 8 cm, which is less than the diameter R₃,for example 12 cm, of the aforementioned optical disk which is theextensively used conventional so-called compact disk having the unifieddisk diameter. The device further comprises a toroidal disk supportingmember 226 having the same outside diameter R₁ as the diameter R₃ of theoptical disk, and a toroidal disk clamping member 227 attached to thedisk supporting member 226 and adapted for clamping the disk 225 incooperation with the disk supporting member 226, (see FIG. 23).

The small size disk 225 has its diameter R₂ less than the diameter ofthe optical disk 2 having the unified disk size or diameter, but it isconfigured in the same manner as the aforementioned optical diskregarding the central opening 225a and the non-record area 225b on theperimeter of the central opening 225a which is clamped onto the disktable of the disk player.

The disk supporting member 226 is formed of synthetic material, such asABS resin, having the prescribed rigidity, and has a thickness aboutequal to that of the optical disk 2. The inner periphery of the disksupporting member 226 is formed with a disk fitting opening 228 forholding the signal record surface 225c adapted to be exposed from thecentral opening 225a of the small size disk 225, as shown in FIGS. 23and 24. On the perimeter of the disk fitting opening 228 and towards oneside 226a of the disk supporting member 226 lying on the same side asthe signal record hold surface 225c when the small size disk 225 isfitted and supported on the supporting member 226, there areprojectingly formed disk supporting pieces 229 on which the disk 225 canbe placed with the outer peripheral portion 225d of the disk 225 notbearing the information signals being supported thereon. Threeequiangular resilient thrusting sections 230 are formed on the perimeterof the disk fitting opening 228 for clamping and supporting the outerperipheral surface of the disk 225. The thrusting sections 230 are eachcomprised of a pair of slits 231, 232 extending radially of the disksupporting member 226, a peripheral slit 233 extending between and nearthe end portions of these slits 231, 232, and a thrusting boss 234 onthe inner periphery of the supporting member 226, such that thethrusting section 230 may be resiliently deformed radially of thesupporting member 226.

On the inner periphery of the other side 226b of the disk supportingmember 226, that is, the surface thereof lying on the same side as aprinted surface 225e opposite to the signal record surface 225c, andbearing the printed information, such as indication of record contents,when the small size disk 225 is fitted and supported by the supportingmember 226, there is formed an attachment portion 235 into which diskclamping projections 237 are fitted. This attachment portion 235 isformed by forming a step on the other side 226b of the disk supportingmember 226 to reduce the thickness thereat. On the outer periphery ofthe attachment portion 235, there are formed a plurality of, herein six,equiangular openings 237 into which are engaged projections 236 formedon the outer periphery of the disk clamping member 227. On the innerperiphery of each of these openings 237, there is formed an engagingrecess 239 into which is engaged an engaging piece 238 provided to thedisk clamping member 227.

On the other surface 226b of the disk supporting member 226 and at aposition corresponding to each of the openings 237, there is provided anindicia 241 for the fitting position corresponding to a mark 240 for thefitting position which is provided on the projection 236 of the diskclamping member 227. The mark 240 and the indicia 241 may be formed bystamping or printing. The projections 236 can be positioned relative tothe openings 237 by having the mark 240 and the indicia 241 registeredwith each other to facilitate the fitting of the projections 236 intothe corresponding openings 237.

The disk clamping member 27 is formed as a disk from resilient syntheticmaterial or a thin metal plate such as a thin stainless steel plate. Onthe inner periphery of the disk clamping member 227, there isprojectingly formed a disk clamping piece 242 for clamping the outerperipheral portion 225d of a small size disk 225 placed on the disksupporting member 226 through the medium of the disk supporting pieces229 in cooperation with the disk supporting member 227, as shown inFIGS. 25, 26 and 27. The projections 236 are formed on the outerperiphery of the disk clamping member 227. On the outer periphery ofthese projections 236, engaging pieces 236a are projectingly formed formating with the perimeter of the openings 237, such that, when theprojections 236 are engaged in the openings 237, no gap is formed aroundthe perimeter of the engaging openings 237. On the distal side of eachof the projections 236, there is formed a cut-out 243 designed to permitthe projection 236 to be resiliently deformed radially of the diskclamping member 227, and the aforementioned engaging piece 238 designedto be protruded into the cut-out 243. The upper surface of theprojection 236 is counterbored at 244 so as to be used as finger restprojections to facilitate the projection 236 to be resiliently deflectedtowards the outer periphery when the projection 236 is fitted into thefitting opening 237 of the disk supporting member 226 to cause theprojection 236 to be engaged in the engaging recess 239.

It is noted that, when only one side of the small size disk 225 isdesigned as the signal record surface 225c, similarly to theaforementioned optical disk, the disk 225 can be attached to the opticalpickup device in the disk player only in a predetermined orientation.For indicating the attachment orientation of the small-size disk, theone surface 226a of the disk supporting member 226 is designed as amirror surface having the appearance similar to that of the signalrecord surface 225c of the disk 225, while the other surface 226b isdesigned as a printed surface bearing printed handling instructionssimilarly to the printed surface 225e of the disk 225.

It is noted that any other means may be employed for indicating theorientation of attachment of the small size disk 225.

The operation of having the small size disk 225 clamped by the abovedescribed apparatus for adapting the disk apparatus will be hereafterexplained.

When the small size disk 225 is to be clamped by the disk size changedevice, it is placed on the disk supporting member 226, with the outerperipheral portion 225d of the disk 225 retained by the disk supportingpieces 229. The projections 236 are then brought to a position inregister with the openings 237 with the aid of the mark 240 and theindicia 241 on the disk supporting member 226, after which the diskclamping members 227 are placed on the attachment portion 235 of thedisk supporting member 226 in register with the opening 237. Followingthis operation, the projections 236 are deformed towards the outerperiphery to widen the cut-outs 243, and the projections 238 are broughtinto positions in register with the openings 237 of the disk supportingmember 226, from the lower side thereof, after which the projections 236are protruded resiliently until the engaging pieces 238 are engaged withthe openings 237 for attachment of the disk clamping member 227 to thedisk supporting member 226 as shown in FIG. 26. When the disk clampingmember 227 is attached to the disk supporting member 226 in this manner,the small size disk 225 is supported within the disk receiving opening228 of the disk supporting member 226 with the outer peripheral portion225d thereof clamped by the disk supporting pieces 229 of the disksupporting member 226 and by the disk clamping pieces 242 of the diskclamping member 227.

With the small size disk 225 being supported by and made as one with thedisk supporting member 226 as described above, the diameter R₂ of thesmall size disk 225 is assimilated to the outside diameter R₁ of thedisk supporting member 226 so that the resulting assembly is equivalentto the optical disk 2 having the unified diameter R₃ and thus can behandled in the same manner as the optical disk 2.

In the present embodiment the disk supporting pieces 229 are provided tothe periphery of the disk receiving opening 228 of the disk supportingmember 226 and the small size disk 225 is placed in position with theaid of the disk supporting pieces 229. However, instead of providing thedisk supporting pieces 229, retaining steps may be formed on the outerperiphery of the disk 225 so as to be engaged with the inner peripheryof the attachment portion 235 for the disk clamping member 227.

A fifth embodiment of the disk size change device of the presentinvention will be hereafter explained.

The embodiment shown herein differs from the previously explained fourthembodiment with reference to the structure for mounting the diskclamping member 227 to the disk supporting member 226. Therefore, in thefollowing description, only the portions different in structure from thefourth embodiment will the explained, and the description of the commonportions will be omitted for simplicity.

The present fifth embodiment is so designed that, after the diskclamping member 227 is fitted to the disk supporting member 226, thedisk clamping member 227 is turned so as to be attached to the disksupporting member 226.

As shown in FIGS. 29 and 31, the disk clamping member 227 of the presentembodiment is provided with a plurality of, herein four, downwardlyprojecting pieces 246 on the outer peripheral portion thereof facing tothe attachment portion 235 of the disk supporting member 226, theseprojecting pieces engaging in mating engaging slots 245 formed on theouter periphery of the attachment portion 235 for the disk clampingmember 227. On the proximate ends of these projecting pieces 246, thereare bored slits 247 adapted to permit the radial deflection of theprojecting pieces 246. The end part of each of the engaging projections246 is formed with an engaging recess 249 into which an engagingprojection 248 engaging with the disk supporting member 226 is engagedwhen the engaging projections 246 are engaged with the mating engagingslots 245.

The outer periphery of the attachment portion 235 for the disk clampingmember is formed with guide pieces 250 adjacent to the engagingprojections 246, these guide pieces being used as the guide when thedisk clamping member 227 is engaged with the disk supporting member 226and the projecting pieces 246 are rotated manually into engagement withthe mating engaging slots 245. On the surface of the guide piece 250,there is formed an indicia 253 for indicating the rotary position foreach of the projecting pieces 246 as by stamping or printing. Thisindicia 253 is associated with indicias 251, 252 on the other surface226b of the disk supporting member 226 indicating non-lock and lockpositions for the projecting pieces 246 with respect to the matingengaging slots 245, respectively.

As shown in FIGS. 29 and 30, there are formed in the disk supportingmember 226 and on the side of the outer periphery of the attachmentportion 235 for the disk clamping member 227 the aforementioned matingengaging slots 245 into which are engaged the projecting pieces 246 ofthe disk clamping member 227. The engaging projecting pieces 246 areintroduced into rotation guide slots 254 formed in continuation withthese mating engaging slots 245. These guide slots are formed so as tobe protruded from the outer periphery of the attachment portion 235 forthe disk clamping member 227 towards the outer periphery of the disksupporting member 226 by a distance corresponding to the protrusion ofthe projecting pieces 246. The outer peripheral edge of the engagingslot 245 is formed with a retaining piece 255 adapted for engaging withthe projecting pieces 246 as shown in FIGS. 29 and 33. The one surfaceof the retaining piece 255 is formed with the aforementioned engagingprojections 248 adapted to be engaged with the mating engaging recesses249 formed at the foremost part of the aforementioned projecting pieces246. The arrangement is so made that, when the engaging projections 248are engaged with the engaging recesses 249, the engaging projectingpieces 246 are completely engaged with the mating engaging slots 245.

The outer periphery of the attachment portion 235 for the disk clampingmember is formed with recesses- 256 by which the disk clamping member227 may be turned within the extent from a position in which theprojecting piece 246 is within the guide opening 254 to a position inwhich it is locked by inter engagement between the guide pieces 250 andthe engaging recess 249 to facilitate prompt and reliable attachment ofthe disk clamping member 227 to the disk supporting member 226.

The operation of having the small size disk 225 clamped by the disk sizechange device is hereafter explained.

For clamping the small size disk 225, the disk is placed on the disksupporting member 226, with the outer peripheral portion 225d thereofretained on the disk supporting pieces 229, similarly to the fourthembodiment described above.

Then, with the indicia 253 on each guide piece 250 in register with therecess 256 of the disk supporting member 226, the disk clamping member227 is placed on the attachment portion 235 of the disk supportingmember 226. When the disk clamping member 227 is placed in this manner,the projecting pieces 246 are received within the guide slots 254, asshown in FIGS. 32 and 33. The disk clamping member 227 is turned fromthis state in the direction of the arrow mark P in FIG. 32, so that theprojecting pieces 246 will be engaged in the mating engaging slots 245.When the disk clamping member 227 is turned until the indicia 253 on theguide opening 254 is in register with the indicia 252, the projectingpieces 246 are engaged with the retaining pieces 255, while the engagingprojections 248 are engaged with the corresponding recesses 249 at theend parts of the projecting pieces 246 to provide for locking of theengaging projecting pieces 246 into the mating engaging slots 245 tocomplete the attachment of the disk clamping member 227 to the disksupporting member 226.

When the disk clamping member 227 is attached to the disk supportingmember 226 in this manner, the small size disk 225 is supported withinthe disk receiving opening 228 of the disk supporting member 226, withthe outer peripheral portion 225d thereof clamped by the disk supportingpieces 229 of the disk supporting member 226 and by the disk clampingpieces 242 of the disk clamping member 227.

With the small size disk 225 being supported by and made as one with thedisk supporting member 226, as described above, the diameter of thesmall size disk 225 is assimilated with the outside diameter of the disksupporting member 226 so that the resulting assembly is equivalent tothe optical disk 2 having the unified diameter and thus can be handledin the same manner as the optical disk 2.

Instead of providing the disk supporting pieces 229, retaining steps maybe provided to the outer peripheral edge of the small size disk 225 soas to be engaged with the inner periphery of the attachment portion 235for the disk clamping member 227.

A sixth embodiment of the apparatus for adapting the disk size accordingto the present invention will be hereafter explained.

The apparatus according to the sixth embodiment is shown in FIGS. 36-43,and is comprised of a small size disk 325 having a diameter of, forexample, 8 cm, which is less than the diameter R₃ for example, 12 cm, ofthe aforementioned optical disk which is the extensively usedconventional so-called compact disk having the unified disk diameter, atoroidal disk supporting member 326 having the same outside diameter R₁as the diameter R₃ of the optical disk and on which the disk 325 issupported, and a disk holding member 327 attached to the disk supportingmember 326 by being rotated, and adapted for holding the disk 325 incooperation with the disk supporting member 326.

The small size disk 325 has its diameter R₂ less than the diameter ofthe optical disk having the unified disk size or diameter, but it isconfigured in the same manner as the aforementioned optical disk withreference to the central opening 325a and the non-record area 325b whichis clamped onto the disk table of the disk player.

The disk supporting member 326 is formed of synthetic resin having theprescribed rigidity, such as ABS resin, and has a thickness about equalto that of the optical disk. The inner periphery of the disk supportingmember 326 is formed with a disk fitting opening 328 for holding thedisk, the signal record surface 325c being adapted to be exposed fromthe central opening 325a of the small size disk 325, as shown in FIGS.36 and 37. On the perimeter of the disk fitting opening 328 and on oneside 326a of the disk supporting member 326 lying flush with the signalrecord surface 325c when the small size disk 325 is fitted and supportedon the supporting member 326, there are projectingly formed disksupporting pieces 329 on which the small size disk 325 can be placedwith the outer peripheral portion 325d of the small size disk 325 notbearing the information signals being supported thereon.

On the other surface 326b of the disk supporting member 326, that is, onthe surface thereof lying flush with the printed surface 325e bearingthe printed indication of the record contents, viz. the surface oppositeto the signal record surface 325c when the small size disk 325 is heldtherein, there is formed on the inner periphery thereof an attachmentportion 330 to which is securely fitted a disk holding member 327. Theattachment portion 330 is formed by forming a step on the other surface326b of the disk supporting member 326 to reduce the thickness thereat.

The outer periphery of the attachment portion 330 is formed with a pairof clamping pieces 332, 333 adapted to support one of a plurality ofattachment engaging pieces 331 as by clamping from the upper and thelower sides, these engaging pieces 331 being formed by bending the outerperipheral portion of the toroidal disk holding member 327 attached tothe outer periphery of the attachment portion 330. On the outerperiphery of the attachment portion 330 for the disk holding member 327,there are formed a plurality of recesses 335 in continuation to thepairs of clamping pieces 332, 333, into which are engaged rotation guidepieces 334 projectingly formed on the outer periphery of the diskholding member 327. Thus the extent of rotation of the rotation guidepieces 334 is controlled by the corresponding recesses 335 to controlthe rotary position of the disk holding member 327. On the innerperiphery of the attachment portion 330 for the disk holding member 327and on the inner peripheral end of the disk holding member 327, thereare projectingly formed cam pieces 338 by which resiliently deflectiblearms 337 each integrally formed with a disk holding piece 336 that maybe projected into the disk fitting opening 328 may be moved radially ofthe disk holding member 327.

The disk holding member 327 rotatably mounted to the attachment portion330 for the disk holding member is prepared by punching a thin metalplate, such as a stainless steel plate, or by molding a syntheticmaterial, into the form of a substantially toroidal piece, as shown inFIG. 38. In the present embodiment, it is formed by punching a stainlesssteel plate.

The rotation guide pieces 334 provided on the disk holding member 327are each formed with a number of radially extending recesses or grooves339 to provide finger rest projections on which a user may act with hisfinger tips to cause the rotation of the disk holding member 327.

The resilient deflectible arm 337 formed with the disk holding member327 at the end thereof is formed by boring a slit 340 along theperiphery of the disk holding member 327. The slit 340 is formed with anarc offset with respect to the center of the disk holding member 327.The resilient deflectible arm 337 thus formed by boring the slit 340 maybe resiliently deflected so that the disk holding piece 336 at the endthereof may be moved radially of the disk holding member 327 with theproximate portion of the disk holding member 327 as center.

The end part of each resilient deflectible arm 337 is extended as arotation operating piece 341 having a boss 341a on one side adapted toengage with a cam piece 338 projectingly mounted to the disk supportingmember 326.

The above described disk holding member 327 is attached to the disksupporting member 326 by engaging the rotation guide pieces 334 in thecorresponding recesses 335, clamping the respective engaging pieces 331between the corresponding sets of clamping pieces 332, 333 and byengaging the rotation operating pieces 341 at the end part of theresilient deflectible arms 337 with the cam pieces 338 and may be turnedalong the peripheral direction within the extent of the recesses 334.

The operating pieces 341 are engaged with engaging projecting pieces338a provided to the cam pieces 338 to prevent incidental extricationthereof towards above.

When only one side of the small size disk 325 is formed as the signalrecord surface 325c, similarly to the above described optical disk, thesmall size disk 325 may be attached to the optical pickup device withinthe disk player only in one attachment orientation. Thus the one side326a of the disk supporting member 326 is designed as the mirror surfacehaving the appearance same as that of the signal record surface 325c ofthe disk 325, while on the other side 326b it is designed as a printedsurface bearing printed handling instructions similarly to the printedsurface 325e of the disk 325.

It is noted that any other indicating means may be used for clarifyingthe attachment orientation of the small size disk 325.

The operation of holding the small size disk 325 by the above describedapparatus for adapting the disk diameter is hereafter explained.

For holding the small size disk 325 in the above described manner, thedisk holding member 327 is turned in the direction of the arrow mark Ras shown in FIG. 39 to cause the operating piece 341 at the end part ofthe resilient deflectible arm 337 to ride on the cam piece 338 to causethe resilient deflectible arm 337 to be turned and offset outwardly ofthe disk supporting member 326 to retract the disk holding piece 336inwardly of the disk supporting member 326. In this state, the smallsize disk 325 is placed on the disk supporting member 326 with the outerperiphery 325d thereof engaged with and retained on the disk supportingpiece 329. The disk holding member 327 is then turned in the directionof the arrow mark Q in FIG. 39 with finger pressure applied to thegrooves 339 formed in each of the rotation control recesses 334. Whenthe disk holding member 327 is turned in this manner, the boss 341a ofthe operating piece 341 is disengaged from the cam pieces 338 to causethe resilient deflective arm 337 to, be turned by spring action backtowards the inner periphery of the disk supporting member 326 to causethe disk holding piece 336 to be protruded into the disk fitting opening328. With the disk holding piece 336 projected in this manner, the smallsize disk 325 has its outer periphery 325d clamped by the disksupporting piece 329 of the disk supporting member 326 and by the diskholding piece 336, as shown in FIGS. 40 and 42, so as to be retainedwithin the fitting opening 328 of the disk supporting member 326.

With the small size disk 325 thus retained and made as one with the disksupporting member 326, the diameter of the small size disk 325 may beassimilated with the outside diameter of the supporting member 326, sothat the resulting assembly is equivalent with the optical disk 2 havingthe unified size or diameter and thus may be handled in the same manneras the aforementioned optical disk.

The foremost parts of the disk holding pieces 336 are formed with bentguide pieces 329 to smooth the operation of holding the small size disk325.

Within the recess 335 of the disk supporting member 326 for regulatingthe rotation of the disk holding member 327, there are formedprojections 345 adapted for engaging with the grooves 339 when the smallsize disk 325 is held therein to regulate the rotation of the diskholding member 327.

In the present embodiment, the operating pieces 341 are provided to theforemost parts of the resilient deflective arms 337 and engaged with thecam pieces 338. Alternatively, however the operating pieces 341 may beomitted and the intermediate portions of the resilient deflective pieces337 may be engaged with the cam pieces 338 to cause the arms 337 to beturned and deflected towards the inside and the outside of the disksupporting member 326.

In the foregoing embodiments, description has been made by taking anexample of an optical disk. However, the present invention is notlimited to the optical disk, but may be extensively applied to anopto-magnetic disk or to a magnetic disk wherein it is necessary tounify the disk to a predetermined diameter.

The outside diameter of the supporting member for the recording mediumand the diameter of the disk fitting opening can be changed to suit tothe unified disk diameter or to the diameter of the disk supported inthe disk holding member.

From the foregoing it is seen that the present invention provides anarrangement in which a disk-like recording medium of a variable size canbe held on the inner periphery of a holder having a unified outsidediameter so that the recording medium of a variable size can be adaptedto the same diameter as that of the recording medium of the unified sizeor diameter. Consequently, the small size disk can be handled in a sameway as a disk of the predetermined size by the present apparatus havingthe unified predetermined outside diameter so that the small size diskcan be loaded to conventional extensively employed disk players.

Also, in accordance with the present invention, the disk-like recordingmedium of variable size can be loaded to one and the same disk playerfor recording and/or reproduction by the same mode of handling andwithout changing the loading unit.

What is claimed is:
 1. An apparatus for adapting the diameter of adisk-like recording medium, comprising a holder having a diameter largerthan that of the disk-like recording medium, said holder being formed soas to hold a non-signal record area on the outer periphery of thedisk-like recording medium to allow signals recorded on the disk-likerecording medium to be read out when the disk-like recording medium isheld by said holder, and wherein said holder includes a supportingmember for the disk-like recording medium which is shaped so that thedisk-like recording medium is placeable thereon, said supporting memberhaving an opening concentric with the disk-like recording medium placedthereon for exposing a signal record area of the disk-like recordingmedium, and clamping members for the disk-like recording mediumremovably mounted to said supporting member and including engaging meansfor engaging with mating engaging portions on said supporting member,said clamping members being mounted to said supporting member byengagement of said engaging means with said mating engaging means so asto clamp the disk-like recording medium in cooperation with saidsupporting member, said supporting member and said clamping membershaving respective thickenesses so that said holder has substantially thesame thicknesses as said disk-like recording medium when said recordingmedium is clamped thereby.
 2. The apparatus according to claim 1 whereinsaid opening in said supporting member is so formed as to cause thetotality of said signal record area of said disk-like recording mediumto be exposed when said signal recording medium is clamped.
 3. Theapparatus according to claim 1 wherein supporting pieces are proved tosaid supporting member so as to protrude from one side of saidsupporting member into the inside of said opening.
 4. The apparatusaccording to claim 3 wherein said clamping members are provided withclamping pieces for clamping said disk-like recording medium incooperation with said supporting pieces.
 5. The apparatus according toclaim 3 wherein said supporting pieces are adapted to support thenon-signal record area on the outer periphery of said disk-likerecording medium.
 6. The apparatus according to claim 1 wherein saidsupporting member has a step having the level difference equivalent tothe thickness of said clamping members mounted thereto.
 7. The apparatusaccording to claim 4 wherein resilient thrusting sections deflectibleresiliently radially of said opening are provided to said supportingmember for thrusting the outer periphery of said disk-like recordingmedium.
 8. The apparatus according to claim 7 wherein said resilientthrusting sections are each formed by a pair of radial slits boredradially from the periphery of said opening and a peripheral slit borebetween near the end parts of said radial slits.
 9. The apparatusaccording to claim 8 wherein thrust projections are provided atsubstantially the center of said thrusting sections for protrudinginwardly of said opening.
 10. The apparatus according to claim 1 whereinsaid mating engaging means of said supporting member include pluralfitting openings and wherein said engaging means of said clampingmembers are fitting pieces provided with engaging projecting piecesengaging with the perimeter of respective fitting openings.
 11. Theapparatus according to claim 10 wherein said engaging means are providedwith a cut-out to permit resilient deflection of said fitting pieces andwherein engaging pieces are protruded into said cut-out to engage withthe perimeter of said fitting opening.
 12. The apparatus according toclaim 11 wherein finger rest means is provided to said clamping membersat said fitting pieces to permit resilient deflection of said fittingpieces.
 13. The apparatus according to claim 1 wherein said supportingmember and said clamping member are provided with marks for indicatingthe relative mounting position thereof.
 14. The apparatus according toclaim 1 wherein said engaging means and said mating engaging means areengaged with each other by relative rotation between said clamping andsupporting members in a prescribed direction.
 15. The apparatusaccording to claim 14 wherein said engaging means includes pluralprojecting pieces provided to said clamping members and wherein saidmating engaging means includes mating engaging grooves in saidsupporting member in which said projecting pieces are engaged.
 16. Theapparatus according to claim 15 wherein said mating engaging grooves areformed with rotational guide openings for guiding said projectingpieces.
 17. The apparatus according to claim 15 wherein the proximateparts of said engaging projecting pieces of said clamping members areformed with slits to permit resilient deflection of said engagingprojecting pieces.
 18. The apparatus according to claim 14 whereinrotation guide pieces are provided to the outer periphery of saidclamping members and wherein said supporting member is provided withgrooves for limiting the rotational extent of said rotation guidepieces.
 19. The apparatus according to claim 15 wherein said clampingmembers are provided with marks indicating the rotational position ofsaid engaging projecting pieces and wherein said supporting member isprovided with indicia showing the non-lock and lock positions of saidprojecting pieces in said mating engaging grooves.